There's a huwge lignite (low grade coal) seam in Germany and this is what is used to remove the overburden.
I seem to remember seeing on DISCOVERY channel (back in the day when I had a tv) a prog called "massive machienes that showed the whole process.
It might be worth watching out for (sky viewers, they often have things on a 3 month or so rolling repeat cycle) or seeing if its downloadable from somewhere on t'internet
Better to regret something you have done - than to regret something you have not done.